Conventionally, there has been known a semiconductor module having a substrate and a semiconductor element (see patent literature 1, for example).
As shown in FIG. 12, the conventional semiconductor module 8 includes: a substrate 810 having an insulating substrate 811, a conductor layer 812 formed on one surface of the insulating substrate 811 and other conductor layers 813, 814 formed at positions spaced apart from the conductor layer 812; a device part (semiconductor element) 820 having a first electrode 821 on one surface (a lower-side surface in FIG. 12) and two second electrodes 822, 823 on the other surface (an upper-side surface in FIG. 12) and making the first electrode 821 and the conductor layer 812 bonded to each other; a wall portion 816 formed along an outer periphery of the insulating substrate 811, a resin portion 860 formed in a state where a resin is disposed in a recessed space which is defined by the insulating substrate 811 and the wall portion 816; a resin-made lid portion 862 disposed on an upper surface of the resin portion 860; and terminals 874, 876 for external connection where one-side ends of the terminals 874, 876 are electrically connected to the other conductor layers 813, 814, and the terminals 874, 876 extend toward the outside (vertically upward) through the resin portion 860 and the lid portion 862 from the one-side ends.
Out of two second electrodes 822, 823 of the semiconductor element 820, one second electrode 822 is electrically connected to the terminal 874 through a wire 870 and the other conductor layer 813, and the other second electrode 823 is electrically connected to the terminal 876 through a wire 872.
The conventional semiconductor module 8 has the resin portion 860 which is formed by disposing a resin in the recessed space defined by the substrate 810 and the wall portion 816 thus providing a semiconductor module having impact resistance.
Recently, in the technical field of semiconductor modules, there has been a demand for a semiconductor module where the structure for resin sealing can be easily formed.
Under such circumstances, inventors of the present invention have come up with a semiconductor module where the structure for resin sealing can be easily formed, and already filed international patent application PCT/JP2015/051655 (hereinafter, referred to as prior patent application) as a prior patent application.
As shown in FIG. 13, a semiconductor module 9 relating to the prior patent application includes:
a first substrate 910 having a first insulating substrate 911 and a first conductor layer 912 which is formed on at least one surface of the first insulating substrate 911;
a device part (semiconductor element) 920 having a first electrode 921 on one surface thereof and a second electrode 922 on the other surface thereof and having the first electrode 921 bonded to the first conductor layer 912;
a second substrate 930 having a second insulating substrate 931 and a second conductor layer 932 formed on at least one surface of the second insulating substrate 931, wherein the second conductor layer 932 has a bonding portion 933 bonded to the second electrode 922 and a surrounding wall portion 934 formed at a position which surrounds the bonding portion 933 as viewed in a plan view in a state where an upper end surface of the surrounding wall portion 934 projects from a bonding surface between the bonding portion 933 and the second electrode 922, and the second substrate 930 is brought into contact with the first substrate 910 by way of the surrounding wall portion 934; and
a resin portion 940 made of a resin and disposed in a space defined by the surrounding wall portion 934 and sandwiched between the first insulating substrate 911 and the second insulating substrate 931.
In the semiconductor module 9 according to the prior patent application, the whole device part 920 is positioned inside a region defined by the surrounding wall portion 934 as viewed in a plan view.
In the semiconductor module 9 according to the prior patent application, the second conductor layer 932 includes the surrounding wall portion 934 formed at the position which surrounds the bonding portion 933 as viewed in a plan view in a state where an upper end surface of the surrounding wall portion 934 projects from the bonding surface between the bonding portion 933 and the second electrode 922. Accordingly, it is unnecessary to additionally prepare a member for forming the structure for resin sealing (for example, the wall portion 816 in the conventional semiconductor module 8) and hence, the structure for resin sealing can be formed easily.
Further, according to the semiconductor module 9 of the prior patent application, the second electrode 922 of the device part 920 is bonded to the second conductor layer 932. Accordingly, by electrically connecting the second conductor layer 932 to a terminal for external connection, it is possible to electrically connect the second electrode 922 of the device part 920 and the terminal for external connection with each other through the second conductor layer 932 having a larger cross-sectional area than a wire and having a lower resistance than the wire. Accordingly, a drawback minimally occurs in the semiconductor module 9 when a large electric current is supplied to the semiconductor module 9 and hence, the semiconductor module 9 according to the prior patent application provides a semiconductor module having higher reliability than conventional semiconductor modules.
Further, in the semiconductor module 9 according to the prior patent application, the second electrode 922 of the device part 920 is bonded to the second conductor layer 932 formed on the one surface of the second insulating substrate 931. With such a configuration, in addition to the radiation of heat generated by the device part 920 to the outside through the first conductor layer 912 and the first insulating substrate 911, such heat can be radiated to the outside through the second conductor layer 932 and the second insulating substrate 931. Accordingly, the semiconductor module 9 according to the prior patent application provides a semiconductor module having higher heat radiation property than conventional semiconductor modules.